At that meeting, Papadopoulos proposed brokering a meeting between Trump and Russian President Vladimir Putin. Trump "hindered this investigation more than George Papadopoulos ever did", Breen said.

He said Papadopoulos' deception required investigators to scour more than 100,000 emails and gigabytes of data to reconstruct the timeline of his contacts with Russians and Russian intermediaries.

The investigation into alleged Russian interference in the United States elections has since been turned over to Special Prosecutor Robert Mueller.

Foreign policy specialist George Papadopoulos "lied in an investigation that was important to national security", said US District Judge Randolph Moss.

"In some ways it constitutes a calculated exercise of self interest over the national interest", the judge said.

Papadopoulos was pictured in March 2016 sitting at a table with Trump, then-campaign adviser Jeff Sessions who went on to become USA attorney general, and other foreign policy campaign advisers.

Papadopoulos pleaded guilty in October to making false statements to Federal Bureau of Investigation agents about his correspondence with Russian nationals and attempts to arrange a meeting between the campaign and Russian officials.

Partly as a result, they said, agents were unable to "effectively question" Misfud when he visited the United States two weeks later. "But they got him, I guess, on a couple of lies, I guess that's what they're saying".

The lawyers argued Papadopoulos lied as he was influenced by the President's aggressive sentiments on the probe.

When Papadopoulos pleaded guilty previous year, he pledged to help the special counsel's office with its investigation.

Outside court on Friday, Papadopoulos' lawyer, Thomas Breen, said his client was a "fool" and had acted "stupidly" by lying to the Federal Bureau of Investigation. "The message here is to check your loyalty, tell the truth, and help the good guys, even if you have to pay a price", Breen said.

The sentencing, coming almost one year after he pleaded guilty to lying to federal agents, ends an important yet mysterious story line in the examination of whether anyone from Trump's team conspired with Moscow to influence the presidential election.